The present invention relates to an ink jet recording device that continuously ejects an ink from a nozzle, and conducts printing on an object to be printed.
One of the ink jet recording devices is of a continuous system in which the ink is continuously ejected from the nozzle, ejected ink particles which are flying are charged, and the charged ink particles are further deflected by an electric field for conducting printing. The ink jet recording device of this system has been extensively popularized for an intended purpose of printing numbers or codes on metal cans or plastic surfaces.
As a related art of this type, there is an ink jet recording device disclosed in Japanese Unexamined Patent Application Publication No. 2009-172932. The ink jet recording device includes a main body, a recording head, and a conduit that couples the main body to the recording head. The main body includes an ink container that stores the ink therein, an ink supply pump that the ink to the recording head from the ink container, a recovery pump that recovers the ink into the ink container from the recording head, and a control unit that controls the operation of the recording device.
The recording head includes a nozzle that ejects the ink supplied from the main body as the ink particles, an electrification electrode that allows the ink particles to be charged, and a deflection electrode that allows the charged ink to be deflected by an electrostatic field, and a gutter that traps unused ink. A tube into which the ink flows, and an electric wiring that transmits an electric signal to the recording head are inserted through the conduit that couples the main body to the recording head.
In the ink jet recording device of this continuous system, a solvent high in volatility such as methyl ethyl ketone or ethanol is used for an ink solvent in order to conduct printing at high speed. Also, when the ink is recovered by the recovery pump, a surrounding air is also sucked from the gutter together with the ink. Because the sucked air is continuously fed to the ink container, there is a need to discharge the air from the ink container.
However, since the volatilized solvent is included in the air sucked together with the ink, if the air sucked from the gutter is discharged out of the ink jet recording device, the ink solvent is also discharged. For that reason, the environment is subject to a load, and the running costs are increased.
Under the circumstances, in order to prevent the ink solvent discharged out of the inkjet recording device from being volatilized, Japanese Unexamined Patent Application Publication No. Sho 60 (1985)-11364 discloses an ink jet recording device having an exhaust line that supplies the air discharged from the ink container to the gutter. In this ink jet recording device, since the exhaust gas is supplied to the gutter, the exhaust gas circulates within the inkjet recording device, and the amount of volatilization of the ink solvent can be reduced. An interior of the main body in which the ink container is present becomes higher in temperature than an interior of the recording head by about 10 to 20° C. For that reason, there is a case in which a temperature of the exhaust gas drops, and the solvent is liquefied while the exhaust gas is being fed to the gutter.
For that reason, there is a need to separate a liquid from the exhaust gas, and as a separation technique thereof, there is a gas-liquid separation device disclosed in Japanese Unexamined Patent Application Publication No. 2003-4343 in which a liquid component that drops by gravity is recovered.
Also, a fine ink mist is mixed in the exhaust gas from the ink container in the ink jet recording device. The ink mist is generated when the ink is recovered from the gutter together with the air. When the exhaust gas is supplied from the ink container to the gutter, the interior of the recording head is dirtied by the ink mist in the exhaust gas. Under the circumstances, as a method of removing the ink mist included in the gas, there is a method of removing a foreign matter from an air disclosed in Japanese Unexamined Patent Application Publication No. 2006-26620.
As illustrated in FIG. 14, the foreign matter removal method is realized by a configuration in which a gas containing a mist is inserted from an inlet 80, and introduced into a solution 82 contained in a container 81, the introduced gas is formed into bubbles 85 by a fine bubble generation unit 83, and discharged into the solution 82, and further the gas as the bubbles 85 goes out an outlet 86. In this configuration, an obstacle unit 84 is present within the solution 82 so that the bubbles 85 cannot easily float. With this configuration, the ink mist is allowed to remain in the solution 82 to enable the removal of the ink mist.